Schedule of Other Liabilities and Deferred Credits (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Deferred Credits and Other Liabilities [Abstract]
Postretirement benefits liability	$ 4,755	$ 23,018
Pension liabilities	41,690	41,279
Deferred gain on vessel sales	112,721	136,238
Other	22,380	34,573
Other liabilities and deferred credits	$ 181,546	$ 235,108